Mackenzie Douthit is officially making every other mom of two kids jealous. The Teen Mom 3 star just gave birth to her second child less than four months ago, and she's already sporting some seriously rock hard abs. I didn't even know abs could look like that four years after pregnancy, let alone mere months.

The competitive cheerleader has been working her ass off (literally -- with squats, because what good is a washboard tummy if you have a droopy hiney?), and it's showing. She posted the most amazing picture to Instagram recently that shows just how awesome her core strength is.

Can you believe there was a baby in there less than four months ago? What the?

Anyway, Mackenzie has her fair share of haters who are worrying about her "unhealthy" decisions. Because apparently once you give birth, your life is supposed to revolve around the infant 24/7, with no time for working out or doing anything at all that you did before having children. Or something.

Mackenzie has always been an exercise fiend, and she's a cheerleader, which means she has a rock solid core. It's impossible to do those moves without core strength, and with that, along with healthy eating choices, comes a very taut tummy.

So haters will hate away, but the truth is, Mackenzie works hard for that bod, and she looks amazing.